The present invention relates to a pneumatic tire, more particularly to a heavy duty radial tire with an improved tread portion having resistance to uneven wear and tear-off and improved wet performance.
In heavy duty radial tires, e.g. truckbus tires which are required to display a large traction, relatively large size polygonal tread blocks are widely used. In such a tire, to improve running noise and wet performance, circumferential grooves and axial grooves are usually inclined. As a result, as shown in FIG. 10, acute angled corners (b) are necessarily formed on the tread blocks. The acute angled corners (b) are worn or torn off relatively easily, which becomes a staring point for uneven wear.
The convention manner to solve this problems of uneven wear is to cut off the corner (b) by a single down slope (e) as shown in FIGS. 11 and 12. However, if the cut-off rubber volume is large, wet performance and tire appearance or tread pattern's image become worse. On the other hand, if the cut-off rubber volume is small, the resistance to uneven wear and tear-off decreases. In the conventional manner, it is difficult to satisfy such irreconcilable requirements.